Optical chromatography ultra small particles by Brownian motion in tilted optical potential induced by bound states in the continuum

TL;DR

This paper demonstrates a novel optical sorting method for ultra-small particles using tilted optical potentials created by bound states in the continuum, enabling size-based separation during Brownian motion.

Contribution

It introduces a new technique utilizing bound states in the continuum to generate optical potentials for sorting nanometer-sized particles.

Findings

Particles with ~1% size difference can be completely separated.

Resonant optical forces significantly influence Brownian dynamics.

Potential for integrated continuous optical sorting platform.

Abstract

We investigate sorting Rayleigh optical particles up to several nanometers in size during Brownian motion in an tilted periodic potential with multiple deep wells. The wells are induced which by optical bound states in the continuum in a system of parallel photonic crystal slabs immersed in a liquid. The Brownian dynamics of the particles is significantly altered by resonant optical forces leading to the complete spatial separation of particles with a size difference of approximately 1% during the diffusion process. In addition, the possibility of creating an integrated platform for continuous optical sorting is discussed.